2-Amino-1,4-dihydropyridine derivatives

ABSTRACT

2-Amino-1,4-dihydropyridines bearing a carbonyl function in the 5-position and being optionally substituted by lower alkyl or phenyl in the 6-position, and the corresponding 2-amino1,4,5,6,7,8-hexahydro-5-oxoquinolines, which derivatives are further substituted by a carbonyl group in the 3-position and optionally substituted in the 4-position by lower alkyl, phenyl, substituted phenyl or a heterocyclic group are anti-hypertensive agents and coronary vessel dilators. The compounds, of which 2amino-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5dicarboxylic acid 3,5-diethyl ester is a representative embodiment, are prepared through condensation of an ylideneacetoacetic acid ester and an amidine.

United States Patent [191 Meyer et al.

[ Dec. 30, 1975 2-AMlNO-l ,4-DIHYDROPYRIDINE DERIVATIVES [75] Inventors: Horst Meyer; Friedrich Bossert,

both of Wuppertal-Elberfeld; Wulf Vater, Opladen; Kurt Stoepel, Wuppertal-Vohwinkel, all of Germany [73] Assignee: Bayer Aktiengesellschaft, Germany [22] Filed: Feb. 1, 1974 [21] Appl. No.: 438,603

Related US. Application Data [62] Division of Ser. No. 336,639, Feb. 28, 1973, Pat. No.

[30] Foreign Application Priority Data Mar. 6, 1972 Germany 221067 [52] US. CL... 260/287 K; 260/256.4 R; 260/283.5;

260/283 CN [51] Int. Cl. C07D 215/32 [58] Field of Search 260/287 R, 256.4 R

[56] References Cited UNITED STATES PATENTS 2,359,329 10/1944 Phillips ..260/287R 3,544,577 12/1970 Seeger ..260/287R OTHER PUBLICATIONS Klingsberg, Heterocyclic Compounds, 1960, pp. 365-376.

Primary Examiner-Paul M. Coughlan, Jr. Assistant Examiner-David E. Wheeler [57] ABSTRACT 2-Amino-l,4-dihydropyridines bearing a carbonyl function in the 5-position and being optionally substituted by lower alkyl or phenyl in the 6-position, and the corresponding 2-amino-l,4,5,6,7,8-hexahydro-5- oxoquinolines, which derivatives are further substituted by a carbonyl group in the 3-position and optionally substituted in the 4-position by lower alkyl, phenyl, substituted phenyl or a heterocyclic group are anti-hypertensive agents and coronary vessel dilators. The compounds, of which 2-amino-6-methyl-4-(3- nitrophenyl)-1 ,4-dihyclropyridine-3 ,S-dicarboxylic acid 3,5-diethyl ester is a representative embodiment, are prepared through condensation of an ylideneacetoacetic acid ester and an amidine.

43 Claims, No Drawings Z-AMINO-1,4-DIHYDROPYRIDINE DERIVATIVES DETAILED DESCRIPTION tion and use and to pharmaceutical compositions con- 1 taining such compounds and useful as antihypertensive agents and coronary vessel dilators.

In particular, the present invention pertains to compounds of the formula ll ll 2 R H 3 ac u Nl-l wherein R is hydrogen; lower alkyl; lower alkenyl; lower alkynyl; phenyl; substituted phenyl in which the substituents are one to three members selected from the group consisting of lower alkyl, lower alkoxy, halogeno, nitro, cyano, trifluoromethyl, azido, carbo(lower alkoxy), lower alkylsulfonyl, lower alkylsulfinyl, lower alkylthio or phenyl; naphthyl; or a heterocyclic ring selected from the group consisting of quinolyl, isoquinolyl, pyridyl, pyrimidyl, thenyl, furyl and pyrryl, said heterocyclic ring being unsubstituted or substituted by one or two members selected from the group consisting of lower alkyl, lower alkoxy and halogeno;

R, when taken independently, is hydrogen, lower alkyl, phenyl or pyridyl;

R when taken independently, is lower alkyl, lower alkoxy lower a|koxy(lower alkoxy), lower alkenyloxy, lower alkynyloxy, amino, lower alkylamino or di(lower alkyl)amino,

R and R when taken together are alkylene of 2 to 4 carbon atoms; and

R is lower alkyl, lower alkoxy, lower alkoxy(lower alkoxy), lower alkenyloxy, lower alkynyloxy, amino, lower alkylamino or di(lower alkyl)amino.

The term lower alkyl denotes a univalent saturated branched or straight hydrocarbon chain containing from l to 6 carbon atoms. Representative of such lower alkyl groups are thus methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec.butyl, tert.butyl, pentyl, isopentyl, neopentyl, tert.pentyl, hexyl, and the like.

The term lower alkenyl denotes a univalent branched or straight hydrocarbon chain containing from 2 to 6 carbon atoms and nonterminal ethylenic unsaturation as, for example, vinyl, allyl, isopropenyl, 2-butenyl, 3-methyl-2-butenyl, Z-pentenyl, 3-pentenyl, 2-hexenyl, 4-hexenyl, and the like.

The term lower alkynyl denotes a univalent branched or straight hydrocarbon chain containing from 2 to 6 carbon atoms and nonterminal acetylenic unsaturation as, for example, ethynyl, 2-propynyl, 4-pentynyl, and the like.

The term lower alkoxy denotes a straight or branched hydrocarbon chain bound to the remainder of the molecule through an ethereal oxygen atom as, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentoxy and hexoxy.

The term lower alkylthio denotes a branched or straight hydrocarbon chain bound to the remainder of the molecule through a divalent sulfur as, for example, methylthio, ethylthio, propylthio, isopropylthio, butylthio, and the like.

The term halogen denotes the substituents fluoro, chloro, bromo and iodo.

As indicated, the present invention also pertains to the physiologically acceptable non-toxic acid addition salts of these basic compounds. Such salts include those derived from organic and inorganic acids such as, without limitation, hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, methane sulphonic acid, acetic acid, tartaric acid, lactic acid, succinic acid, citric acid, malic acid, maleic acid, sorbic acid, aconitic acid, salicylic acid, phthalic acid, embonic acid, enanthic acid, and the like.

According to the present invention, the foregoing compounds are prepared by reacting a dicarbonyl compound of the formula:

wherein R, R and R are as herein defined, with an amidine of the formula:

in which R is as herein defined. The condensation proceeds smoothly in good yields simply by heating the two components, generally in the presence of an inert organic solvent such as methanol, ethanol, propanol and similar alkanols, ethers such as dioxane and diethyl ether, glacial acetic acid, pyridine, dimethylformamide, dimethylsulfoxide, acetonitrile and the like. The reaction is conducted at temperatures of from 20 to 250C, conveniently at the boiling point of the solvent, and while elevated pressure may be utilized, normal atmospheric pressure is generally satisfactory. The reactants are employed in substantially equimolar amounts. The amidine reactant can be employed as the free base or in the form of a salt such as the hydrohalide salts with the amidine being liberated from the salt through treatment with a basic agent such as an alkali metal alkoxide. The dicarbonyl reagent can be utilized as such or generated in situ by the reaction of an aldehyde of the formula RCHO and a B-dicarbonyl compound of the formula R'COCH COR It is rather surprising that the above described condensation produces the desired compounds in such good yields and with such high purity for while it is known that a benzylideneacetoacetic acidester can be condensed with an amino crotonic acid ester to yield a 1,4-dihydropyridine (Knoevenagel, Ber. 31, 743, 1898), it would be expected from, for example, Silversmith, J. Org. Chem. 27, 4090 (1952) that the addition of an amidine to an a,B-unsaturated keto compound would yield the dihydropyrimidine derivative rather than the dihydropyridine derivative.

Many of the dicarbonyl compounds utilized as one of the reactants are known to the art and the others can either be generated in situ as herein described or prepared according to methods well known to the art, see for example Org. Reaction XV, 204 et seq. (1967). Typical of this reactant are the following compounds:

benzylideneacetoacetic acid methyl ester,

ethylideneacetoacetic acid methyl ester, isopropylideneacetoacetic acid methyl ester, 2-nitrobenzylideneacetoacetic acid methyl ester, 2-nitrobenzylideneacetylacetone, benzylideneacetylacetone, 3-nitrobenzylideneacetoacetic acid methyl ester, 3-nitrobenzylideneacetoacetic acid propargyl ester, 3-nitrobenzylideneacetoacetic acid allyl ester, 3-nitrobenzylideneacetoacetic acid B-methoxyethyl ester, 3-nitrobenzyldieneacetoacetic ester, 3-nitrobenzylideneacetoacetic acid isopropyl ester, 3-nitrobenzylideneacetylacetone, 4-nitrobenzylideneacetylacetone, 4-nitrobenzylideneacetoacetic acid B-propoxyethyl ester,

4-nitrobenzylideneacetoacetic acid n-propyl ester,

3-nitro-6-chlorobenzylideneacetoacetic acid methyl ester,

2-cyanobenzylideneacetoacetic acid methyl ester,

2-cyanobenzylideneacetoacetic acid methyl ester,

2-cyanobenzylideneacetoacetic acid ethyl ester,

2-cyanobenzylidenepropionylacetic acid ethyl ester,

3-cyanobenzylideneacetoacetic acid methyl ester,

3-nitro-4-chlorobenzylideneacetylacetone,

3-nitro-4-chlorobenzylideneacetoacetic acid t-butyl ester,

3-nitro-4-chlorobenzylideneacetoacetic acid methyl ester, 2-nitro-4-methoxybenzylideneacetoacetic methyl ester, 2-cyano-4-methylbenzylideneacetoacetic acid ethyl ester,

2-azidobenzylideneacetoacetic acid ethyl ester,

3-azid0benzylideneacetylacetone,

2-methylmercaptobenzylideneacetoacetic acid isopropyl ester,

2-sulphinylmethylbenzylideneacetoacetic acid ethyl ester,

2 sulphonylbenzylidenemethylacetoacetic acid allyl ester,

4-sulphonylmethylbenzylideneacetoacetic acid ethyl ester,

naphth-l-ylideneacetoacetic acid methyl ester,

naphth-l-ylideneacetoacetic acid ethyl ester,

naphth-2-ylideneacetoacetic acid ethyl ester, 2-ethoxynaphth-l-ylideneacetoacetic acid methyl acid B-ethoxyethyl acid ester, Z-methoxynaphth-l-ylideneacetoacetic acid ethyl ester,

5-bromonaphth-l-ylideneacetoacetic acid methyl ester,

4 a-pyridylmethylideneacetoacetic acid methyl ester, a-pyridylmethylideneacetoacetic acid ethyl ester, a-pyridylmethylideneacetoacetic acid allyl ester, a-pyridylmethylideneacetoacetic acid cyclohexyl ester,

B-pyridylmethylideneacetoacetic yethyl ester,

y-pyridylmethylideneacetoacetic acid methyl ester,

6-methyl-a-pyridylmethylideneacetoacetic acid ethyl ester,

4,6-dimethoxypyrimid-5-ylmethylideneacetoacetic acid ethyl ester,

then-2-ylmethylideneacetoacetic acid ethyl ester,

fur-2-ylmethylideneacetoacetic acid allyl ester,

pyrr-2-ylthylideneacetoacetic acid methyl ester,

nitrobenzylidenepropionylacetic acid ethyl ester,

a-pyridylmethylidenepropionylacetic acid ethyl ester,

a-pyridylmethylidenepropionylacetic acid methyl ester,

a-pyridylmethylideneacetylacetone,

2-, 3- or 4-methoxybenzylideneacetoacetic acid ethyl ester,

2-, 3- or 4-methoxybenzylideneacetylacetone,

Z-methoxybenzylideneacetoacetic acid allyl ester,

Z-methoxybenzylideneacetoacetic acid allyl ester,

2-methoxybenzylideneacetoacetic acid propargyl ester,

2-methoxybenzylideneacetoacetic acid B-methoxyethyl ester,

2-isopropoxybenzylideneacetoacetic acid ethyl ester,

3-butoxybenzylideneacetoacetic acid methyl ester,

3,4,5-trimethoxybenzylideneacetoacetic acid allyl ester,

Z-methylbenzylidenepropionylacetic acid methyl ester,

2-, 3- or 4-methylbenzylideneacetoacetic acid ethyl ester,

2-methylbenzylideneacetoacetic yethyl ester,

Z-methylbenzylideneacetoacetic acid B-propoxyethyl ester,

2-methylbenzylideneacetylacetone,

3,4-dimethoxy-5-br0mobenzylideneacetoacetic acid ethyl ester,

2-, 3- or 4-chlorobenzylideneacetoacetic acid ethyl ester,

2-, 3- or 4-bromobenzylideneacetoacetic acid ethyl ester,

2-, 3- or 4-fluorobenzylideneacetoacetic acid ethyl ester,

2-fluorobenzylideneacetoacetic acid methyl ester,

3-chlorobenzylideneacetylacetone,

3-chlorobenzylidenepropionylacetic acid ethyl ester,

3-chlorobenzylideneacetoacetic acid ethyl ester,

2-chlorobenzylideneacetoacetic acid allyl ester,

2-, 3- or 4-trifluoromethylbenzylideneacetoacetic acid isopropyl ester,

3-trifluoromethylbenzylideneacetoacetic acid methyl ester,

2-carbethoxybenzylideneacetoacetic acid ethyl ester,

3-carbomethoxybenzylideneacetoacetic acid methyl ester,

4-carboisopropoxybenzylideneacetoacetic acid isopropyl ester,

4-carbomethoxybenzylideneacetoacetic acid allyl ester,

3-nitrobenzylidenecyclohexanel ,3-dione, and

acid ,B-methoxacid ,B-methox- 3-nitrobenzylidenecycloheptane-l ,3-dione.

The amidine reactants are similarly known or can be readily produced according to known methods, see for example McElvain et al., J.A.C.S., 73, 2760 (l95l). Typical of these reactants are the following:

amidinoacetic acid methyl ester,

amidinoacetic acid ethyl ester,

amidinoacetic acid n-propyl ester,

amidinoacetic acid isopropyl ester,

amidinoacetic acid cyclohexyl ester,

amidinoacetic acid B-methoxyethyl ester,

amidinoacetic acid a-ethoxyethyl ester,

amidinoacetic acid B-ethoxyethyl ester, amidinoacetic acid propargyl ester, and amidinoacetamide.

As noted above, the compounds of the present invention demonstrate the ability to reduce blood pressure and to effect a dilation of the coronary vessels. They can accordingly be used where either or both of these effects are desired. Thus upon parenteral, oral or sublingual administration, the compounds produce a distinct and long lasting dilation of the coronary vessels which is intensified by a simultaneous nitrite-like effect of reducing the load on the heart. The effect on heart metabolism is thus one of energy saving. In addition, the compounds lower the blood pressure of normotonic and hypertonic animals and can thus be used as antihypertensive agents. These properties can be conveniently observed in well known laboratory models. Thus for example the coronary vessel dilation effect can be observed by measuring the increase in oxygen saturation in the coronary sinus in the narcotized, heart catheterized dog, as shown in the following table:

4-(3-nitrophenyl)- l,4-dihydropyridine-3,5-dicarboxylic acid diethyl ester The hypotensive activity of the present compounds can be observed by measuring the blood pressure of hypertensive rats following administration of the compounds. The following table demonstrates the dose which results in at least a l5 mm Hg reduction in blood pressure of such animals:

Compound Dose(mg/kg) 2-amino-6-methyI-4-phen l-l,4- I.0 dihydropyridine-3,5-dicar oxylic acid diethyl ester 2-amino-6-methyl-4-( Z-nitrophenyll,4-dihydropyridine-3 ,5 -dicarboxylic acid 3-ethyl ester S-methyl ester 2-amino-6-methyl-4-(2-methoxyphenyl)- l,4-dihydropyridine-3 ,S-dicarboxylic acid diethyl ester 2-amino-6-methyl-4-(Z-cyanophenyl )-l ,4-

-continued Compound Dose( mg/kg) dihydropyridine-3,5-dicarboxylic acid diethyl ester 2amino-6-methyl-4-( Z-trifluoromethylphenyl )l ,4-dihydropyridine-3,5-dicarboxylic acid diethyl ester 2-amino-6methyl-4-( 3-nitrophenyl I ,4- dihydropyridine-3,S-dicarboxylic acid diethyl ester 2-amino-6-methyl-4-( 3-nitrophenyl l ,4- dihydropyridine-3,S-dicarboxylic acid 3ethyl ester S-methyl ester 2-amino-6-methyl-4-(3-nitrophenyl )-l ,4- dihydropyridine-3,5-dicarboxylic acid 3-ethyl ester S-B-methoxyethyl ester 2-amino 5 -acetyl-6-methyI-4-( 3-nitro phenyl l ,4-dihydropyridine-3-carboxylic acid ethyl ester 2-amino-6-methyl-4-( 3-nitro-6-chlorophenyl l ,4-dihydropyridine-3 ,5dicarboxylic acid 3-ethyl ester S-methyl ester The toxicity of the compounds is remarkably low. Thus for example thetoxic dose of 2-amino-6-methyl- 4-(2-trifluoromethylphenyl)-l ,4-dihydropyridine-3,5- dicarboxylic acid diethyl ester in mice upon oral administration is greater than 1000 mg/kg.

In addition to the effect on blood pressure and coronary vessels, the compounds also lower the excitability of the stimulus formation and excitation conduction system within the heart so that an antifibrillation action is observed at therapeutic doses. The tone of the smooth muscle of the vessels is also greatly reduced. This vascular-spasmolytic action can be observed in the entire vascular system as well as in more or less isolated and circumscribed vascular regions such as the central nervous system. In addition, a strong muscular-spasmolytic action is manifested in the smooth muscle of the stomach, the intestinal tract, the urogenital tract and the respiratory system. Finally, there is some evidence that the compounds influence the cholesterol level and lipid level of the blood. These effects complement one another and the compounds are thus highly desirable as pharmaceutical agents to be used in the treatment of hypertension and conditions characterized by a constriction of the coronary blood vessels.

Pharmaceutical compositions for effecting such treatment will contain a major or minor amount, e.g. from 95 to 0.5%, of at least one 2-amino-l,4-dihydropyridine as herein defined in combination with a pharmaceutical carrier, the carrier comprising one or more solid, semi-solid or liquid diluent, filler and formulation adjuvant which is nontoxic, inert and pharmaceutically acceptable. Such pharmaceutical compositions are preferably in dosage unit form; i.e. physically discrete units containing a predetermined amount of the drug corresponding to a fraction or multiple of the dose which is calculated to produce the desired therapeutic response. The dosage units can contain one, two, three four or more single doses or, alternatively, one-half, third or fourth of a single dose. A single dose preferably contains an amount sufficient to produce 0 the desired therapeutic effect upon administration at condition of the recipient, the route of administration and the nature and gravity of the illness, generally the daily dose will be from about 0.001 to about 2 mg/kg, preferably 0.005 to 1.0 mg/kg, when administered par enterally and from about 0.1 to about 20 mg/kg, preferably 0.5 to 10 mg/kg, when administered orally. in some instances a sufficient therapeutic effect can be obtained at lower doses while in others, larger doses will be required.

Oral administration can be effected utilizing solid and liquid dosage unit forms such as powders, tablets, dragees, capsules, granulates, suspensions, solutions and the like.

Powders are prepared by comminuting the compound to a suitable fine size and mixing with a similarly comminuted pharmaceutical carrier such as an edible carbohydrate as for example starch, lactose, sucrose, glucose or mannitol. Sweetening, flavoring, preservative, dispersing and coloring agents can also be present.

Capsules are made by preparing a powder mixture as described above and filling formed gelatin sheaths. Glidants and lubricants such as colloidal silica, talc, magnesium stearate, calcium stearate or solid polyethylene glycol can be added to the powder mixture before the filling operation. A disintegrating or solubilizing agent such as agar-agar, calcium carbonate or sodium carbonate can also be added to improve the availability of the medicament when the capsule is ingested.

Tablets are formulated for example by preparing a powder mixture, granulating or slugging, adding a lubricant and disintegrant and pressing into tablets. A powder mixture is prepared by mixing the compound, suitably comminuted, with a diluent or base as desbribed above, and optionally with a binder such as carboxymethyl cellulose, an alginate, gelatin, or polyvinyl pyrrolidone, a solution retardant such as paraffin, a resorption accelerator such as a quaternary salt and/or an absorption agent such as bentonite, kaolin or dicalcium phosphate. The powder mixture can be granulated by wetting with a binder such as syrup, starch paste, acacia mucilage or solutions of cellulosic or polymeric materials and forcing through a screen. As an alternative to granulating, the powder mixture can be run through the tablet machine and the resulting imperfectly formed slugs broken into granules. The granules can be lubricated to prevent sticking to the tablet forming dies by means of the addition of stearic acid, a stearate salt, talc or mineral oil. The lubricated mixture is then compressed into tablets. The midicaments can also be combined with free flowing inert carriers and compressed into tablets directly without going through the granulating or slugging steps. A clear or opaque protective coating consisting of a sealing coat of shellac, a coating of sugar or polymeric material and a polish coating of wax can be provided. Dyestuffs can be added to these coatings to distinguish different unit dosages.

Oral fluids such as solutions, syrups and elixirs can be prepared in dosage unit form so that a given quantity contains a predetermined amount of the compound. Syrups can be prepared by dissolving the compound in a suitably flavored aqueous sucrose solution while elixirs are prepared through the use of a nontoxic alcoholic vehicle. Suspensions can be formulated by dispersing the compound in a nontoxic vehicle. Solubilizers and emulsifiers such as ethoxylated isostearyl alcohols and polyoxyethylene sorbitol esters, preservatives, flavor additives such as peppermint oil or saccharin, and the like can also be added.

Where appropriate, dosage unit formulations for oral administration can be microencapsulated. The formulation can also be prepared to prolong or sustain the release as for example by coating or embedding particulate material in polymers, Wax or the like.

Parenteral administration can be effected utilizing liquid dosage unit forms such as sterile solutions and suspensions intended for subcutaneous, intramuscular or intravenous injection. These are prepared by suspending or dissolving a measured amount of the compound in a nontoxic liquid vehicle suitable for injection such as an aqueous or oleaginous medium and sterilizing the suspension or solution. Alternatively a measured amount of the compound is placed in a vial and the vial and its contents are sterilized and sealed. An accompanying vial or vehicle can be provided for mixing prior to administration. Nontoxic salts and salt solutions can be added to render the injection isotonic. Stabilizers, preservatives and emulsifiers can also be added.

The following examples will serve to further typify the nature of the present invention through the presentation of specific embodiments. These examples should not be construed as a limitation on the scope of Applicants invention since the subject matter regarded as the invention is set forth in the appended claims.

EXAMPLE 1 Upon boiling a solution of 21.8 g of benzylideneacetoacetic acid ethyl ester and 13.0 g of amidinoacetic acid ethyl ester in 150 ml of ethanol for 2 hours, 2-amino-6-methy1-4-phenyl-1,4-dihydropyridine-3,5-dicarboxylic acid diethyl ester of melting point 164C (alcohol) is obtained.

Yield: 67% of theory.

EXAMPLE 2 Upon boiling a solution of 24.9 g of 2-nitrobenzylideneacetoacetic acid methyl ester and 13.0 g of amidinoacetic acid ethyl ester in ml of ethanol for 1 hour, 2-amino-6-methyl-4-(2-nitrophenyl)-l ,4-dihydropyridine-3,5-dicarboxylic acid 3-ethyl ester 5- methyl ester of melting point 168C (alcohol) is obtained.

Yield: 59% of theory.

EXAMPLE 3 Upon boiling a solution of 24.8 g of 2-methoxybenzylideneacetoacetic acid ethyl ester and 13.0 g of amidinoacetic acid ethyl ester in ml of ethanol for 1 hour, 2-amino-6-methyl-4-(2-methoxyphenyl)-l,4- dihydropyridine-3,S-dicarboxylic acid diethyl ester of melting point 170C (ethanol) is obtained.

Yield: 65% of theory.

EXAMPLE 4 Upon boiling a solution of 23.2 g of 2-methylbenzylideneacetoacetic acid ethyl ester and 13.0 g of amidinoacetic acid ethyl ester in 150 ml of ethanol for 2 hours, 2-amino-6-methyl-4-(2-methylphenyl)-l,4- dihydropyridine-3,S-dicarboxylic acid diethyl ester of melting point 130C (ethanol) is obtained.

Yield: 71% of theory.

EXAMPLE Upon boiling a solution of 24.3 g of 2-cyanobenzylideneacetoacetic acid ethyl ester and 13.0 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 2 hours, 2-amino-6-methyl-4-(2-cyanophenyl)-1,4- dihydropyridine-3,S-dicarboxylic acid diethyl ester of melting point 208C (ethanol) is obtained.

Yield: 54% of theory.

EXAMPLE 6 EXAMPLE 7 Upon boiling a solution of 12.6 g of 3-chlorobenzylideneacetoacetic acid ethyl ester and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 2 hours, 2-amino-6-methyl-4-(3-chlorophenyl)-1,4- dihydropyridine-3,S-dicarboxylic acid diethyl ester of melting point 157159C (ethanol) is obtained.

Yield: 62% of theory.

EXAMPLE 8 Upon boiling a solution of 13.2 g of 4-methylmercaptobenzylideneacetoacetic acid ethyl ester and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 1 hour, 2-amino-6-methy1-4-(4-methylmercaptophenyl)-l,4-dihydropyridine-3,S-dicarboxylic acid diethyl ester of melting point 165C (ethyl acetate/petroleum ether) is obtained.

Yield: 49% of theory.

EXAMPLE 9 Upon boiling a solution of 26.3 g of 3-nitrobenzylideneacetoacetic acid ethyl ester and 13.0 g of amidinoacetic acid ethyl ester in 200 m1 of ethanol for 1 hour, 2-amino-6-methy1-4-(3-nitrophenyl)-1,4-dihydropyridine 3,5-dicarboxylic acid diethyl ester of melting point 169C (ethanol) is obtained.

Yield: 58% of theory.

EXAMPLE 10 Upon boiling a solution of 24.9 g of 3-nitrobenzylideneacetoacetic acid methyl ester and 13.0 g of amidinoacetic acid ethyl ester in 180 ml of ethanol for 1 hour, 2-amino-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridinc-3,5-dicarboxylic acid 3-ethyl ester 5- methyl ester of melting point 124C is obtained.

Yield: 59% of theory.

EXAMPLE 1 1 Upon heating a solution of 13.8 g of 3-nitrobenzylideneacetoacetic acid isopropyl ester and 6.5 g of amidinoacetic acid ethyl ester in 150 ml of ethanol for 2 hours, 2-amino-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-ethyl 5-isopropyl ester of melting point 206-207C (alcohol) is obtained.

Yield: 62% of theory.

EXAMPLE 12 Boiling a solution of 10.9 g of 3-nitrobenzylideneacetoacetic acid propargyl ester and 5.2 g of amidinoacetic acid ethyl ester in ml of ethanol for 1 hour yields 2-amino-6-methyl-4-(3-nitrophenyl)-1,4- dihydropyridine-3,S-dicarboxylic acid 3-ethyl ester S-propargyl ester of melting point 181C (ethanol).

Yield: 59% of theory.

EXAMPLE 13 Heating a solution of 14.6 g of 3-nitrobenzylideneacetoacetic acid B-methoxyethyl ester and 6.5 g of amidinoacetic acid ethyl ester in 150 ml of ethanol for 1 hour yields 2-amino-6-methyl-4-(3-nitrophenyl)- 1,4-dihydropyridine-3,S-dicarboxylic acid 3-ethyl ester S-B-methoxyethyl ester of melting point 179C (ethyl acetate/petroleum ether).

Yield: 58% of theory.

EXAMPLE 14 Upon boiling a solution of 7.6 g of 3-nitrobenzaldehyde, 5.0 g of acetylacetone and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 2 hours, 2- amino-5-acetyl-6-methyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3-carboxylic acid ethyl ester of melting point 217C (ethanol) is obtained.

Yield: 48% of theory.

EXAMPLE 15 Upon boiling a solution of 14.2 g of 3-nitro-6- chlorobenzylideneacetoacetic acid methyl ester and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 1 hour, 2-amino-6-methyl-4-(3-nitro-6- chlorophenyl)-1,4-dihydropyridine-3.,5-dicarboxylic acid 3-ethyl ester S-methyl ester of melting point 124C (ethanol) is obtained.

Yield: 73% of theory.

EXAMPLE 16 Upon boiling a solution of 10.4 g of 2-furfurylideneacetoacetic acid ethyl ester and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 2 hours, 2-amino-6-methyl-4-(fur-2-yl)-l ,4-dihydropyridine-3,S-dicarboxylic acid diethyl ester of melting point 183C (isopropanol) is obtained.

Yield: 78% of theory.

EXAMPLE 17 Upon boiling a solution of 14.0 g of benzylidenebenzoylacetic acid ethyl ester and 6.5 g of amidinoacetic acid ethyl ester in 150 ml of ethanol for 2 hours, 2- amino-4,6-diphenyl-1 ,4-dihydropyridine-3 ,S-dicarboxylic acid ethyl ester of melting point 183C (ethanol) is obtained.

Yield: 48% of theory.

EXAMPLE 18 Upon heating a solution of 15.6 g of ethylideneacetoacetic acid ethyl ester and 13.0 g of amidinoacetic acid ethyl ester in 100 m1 of ethanol for 2 hours, 2-amino-4,6-dimethyl-1,4-dihydropyridine- 3,5-dicarboxylic acid diethyl ester of melting point C (isopropanol) is obtained.

Yield: 59% of theory.

EXAMPLE 19 Upon boiling a solution of 2.8 g of acetaldehyde, 5.6 g of cyclohexane-1,3-dione and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 2 hours, 2- amino-4-methyl-l ,4,5 ,6,7 ,S-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester of melting point 236C (ethanol) is obtained.

Yield: 53% of theory.

EXAMPLE Upon boiling a solution of 7.6 g of 3-nitrobenzaldehyde, 5.6 g of cyclohexane-l,3-dione and 6.5 g of amidinoacetic acid ethyl ester for 1 hour, 2-amino-4- (3-nitrophenyl)-l ,4,5 ,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester of melting point 260C is obtained (alcohol/DMF).

Yield: 61% of theory.

EXAMPLE 21 Upon boiling a solution of 7.1 g of 3-chlorobenzaldehyde, 5.6 g of cyclohexane-l ,3-dione and 6.5 g of amidinoacetic acid ethyl ester in 150 ml of ethanol for 2 hours, 2-amino-4-(3-chlorophenyl)-1,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester of melting point 266C (ethanol/DMF) is obtained.

Yield: 66% of theory.

EXAMPLE 22 Upon boiling a solution of 5.3 g of pyridin-2-aldehyde, 5.6 g of cyclohexane-l,3-dione and 6.5 g of amidinoacetic acid ethyl ester in ISO ml of alcohol for 3 hours, 2-amin'o-4(a-pyridyl)-l ,4,5,6,7,8-hexahydro- 5 oxoquinoline-3-carboxylic acid ethyl ester of melting point 260C is obtained (alcohol).

Yield: 46% of theory.

EXAMPLE 23.

Upon heating a solution of 7.6 g of 2-nitrobenzaldehyde, 5.6 g of cyclohexane-l ,3-dione and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 2 hours, 2-amino-4-(2-nitrophenyl)-l,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester of melting point 212C (alcohol) is obtained.

Yield: 69% of theory.

EXAMPLE 24 Upon heating a solution of 7.9 g of quinolin-4-aldehyde, 5.6 g of cyclohexane-l,3-dione and 6.5 g of amidinoacetic acid ethyl ester in 150 ml of ethanol for 3 hours, 2-amino-4-(quinol-4-yl)-1,4,5,6,7,8-hexahydro-5-oxoquinolinecarboxylic acid 3-ethyl ester of melting point 260C (ethanol/DMF) is obtained.

Yield: 81% of theory.

EXAMPLE 25 EXAMPLE 26 Upon boiling a solution ,of 6.3 g of l-naphthaldehyde, 4.5 g of cyclohexane-l ,3-dione and 5.2 g of amidinoa- 12 cetic acid ethyl ester in 150 ml of ethanol for 2 hours, 2-amino-4-(naphth-1-yl)-l ,4,5 ,6,7,8-hexahydro-5- oxoquinoline-3-carboxylic acid ethyl ester of melting point 279C (ethanol/DMF) is obtained.

Yield: 64% of theory.

EXAMPLE 27 Upon heating a solution of 6.3 g of isoquinolin-laldehyde, 4.5 g of cyclohexane-l,3-dione and 5.2 g of amidinoacetic acid ethyl ester in ml of ethanol for 2 hours, 2-amino-4-(isoquinol-l-yl)-l,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester of melting point 272C (ethanol) is obtained.

EXAMPLE 28 Upon heating a solution of 4.8 g of 6-methylpyridin- 2-aldehyde, 4.5 g of cyclohexanel ,3-dione and 5.2 g of amidinoacetic acid ethyl ester in ml of ethanol for 8 hours, 2-amino-4-(6-methylpyrid-2-yl)-l,4,5,6,7,8- hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester of melting point 260C (ethanol/DMF) is obtained.

Yield: 46% of theory.

EXAMPLE 29 Upon boiling a solution of 13.3 g of 3-nitrobenzylideneacetoacetic acid ethyl ester and 5.1 g of amidinoacetamide in ml of ethanol for 2 hours, 2-amino-6-methyl-5-carbethoxy-4-( 3-nitrophenyl l,4-dihydropyridine-3-carboxylic acid amide of melting point 260C (alcohol) is obtained.

Yield: 52% of theory.

EXAMPLE 30 Upon heating a solution of 6.5 g of 2-cyanobenzaldehyde, 5.6 g of cyclohexane-l ,3-dione and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 5 hours, 2-amino-4-(2-cyanophenyl)-l,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester of melting point C (ethanol) is obtained.

Yield: 49% of theory.

EXAMPLE 31 Upon heating a solution of 26.3 g of 3-nitrobenzylideneacetoacetic acid ethyl ester and 14.4 g of amidinoacetic acid isopropyl ester in 250 ml of ethanol for '2 hours, 2-amino-6-methyl-4-(3-nitrophenyl)-l ,4- dihydropyridine-3,S-dicarboxylic acid 3-isopropyl ester 5-ethyl ester of melting point l756C (ethanol) is obtained.

Yield: 77% of theory.

EXAMPLE 32 Heating a solution of 14.3 g of 2-trifluoromethylbenzylideneacetoacetic acid ethyl ester and 7.2 g of amidinoacetic acid isopropyl ester in 150 ml of ethanol for 1 hour yields 2-amino-6-methyl-4-(2-trifluoromethylphenyl )-l ,4-dihydropyridine-3,S-dicarboxylic acid 3-isopropyl ester S-ethyl ester of melting point 106C.

Yield: 49% of theory.

EXAMPLE 33 Upon heating a solution of 13.9 g of 3-nitrobenzylideneacetoacetic acid isopropyl ester and 7.2 g of amidinoacetic acid isopropyl este'r in ml of ethanol for 1 hour, 2-amino-6-methyl-4-(3nitrophenyl)-l,4- dihydropyridine-3,5-dicarboxylic acid diisopropyl ester of melting point 122C (ether) is obtained.

13 Yield: 62% of theory.

EXAMPLE 34 EXAMPLE 35 Upon heating a solution of 12.5 g of 3-nitrobenzylideneacetoacetic acid methyl ester and 7.2 g of amidinoacetic acid isopropyl ester in 150 ml of ethanol for 2 hours, 2-amino-6-methyl-4-(3-nitrophenyl)-l,4- dihydropyridine-3,S-dicarboxylic acid 3-isopropyl ester S-methyl ester of melting point 167C (ethanol) is obtained.

Yield: 82% of theory.

EXAMPLE 36 Upon heating a solution of 1 1.0 g of 2-trifluoromethyl-4-nitrobenzaldehyde, 5.6 g of cyclohexane-l ,3-dione and 6.5 g of amidinoacetic acid ethyl ester in 250 ml of ethanol of 2 hours, 2-amino-4-(2-trifluoromethyl-4- nitrophenyl)-1,4,5 ,6,7 ,8-hexahydro-5-oxoquinoline-3- carboxylic acid ethyl ester of melting point 264C (ethanol) is obtained.

Yield: 62%of theory.

EXAMPLE 37 Heating a solution of 13.2 g of 3-nitrobenzylideneacetoacetic acid ethyl ester and 7.2 g of amidinoacetic acid n-propyl ester in 200 ml of ethanol for 2 hours yields 2-amino-6-methyl-4-(3-nitrophenyl)- 1,4-dihydropyridine-3,5-dicarboxylic acid 3-n-propyl ester S-ethyl ester of melting point 168C (ethanol).

Yield: 79% of theory.

EXAMPLE 38 Boiling a solution of 8.5 g of 6-nitroveratraldehyde, 4.0 g of cyclohexane-l,3-dione and 5.2 g of amidinoacetic acid ethyl ester in 150 ml of ethanol for 1 hour yields 2-amino-4-(2-nitro-4,5-dimethoxyphenyl)- 1,4,5 ,6,7,S-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester of melting point 261C (ethanol).

Yield: 52% of theory.

EXAMPLE 39 Boiling a solution of 13.2 g of 3-nitrobenzylideneacetoacetic acid ethyl ester and 8.0 g of amidinoacetic acid ,B-methoxyethyl ester in 200 ml of ethanol for 2 hours yields 2-amino-6-methyl-4-(3-nitrophenyl)-l,4-dihydropyridine-3,S-dicarboxylic acid 3- (B-methoxyethyl) ester 5-ethyl ester of melting point 174C.

Yield: 59% of theory.

EXAMPLE 40 Upon heating a solution of 6.1 g of biphenyl-Z-aldehyde, 3.8 g of cyclohexane-1,3-dione and 5.1 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 1 hour, 2-amino-4-(biphenyl-2-yl)-l,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester of melting point 248C (ethanol) is obtained.

Yield: 45% of theory.

EXAMPLE 41 Boiling a solution of 13.4 g of (l-naphthylidene)- acetoacetic acid ethyl ester and 6.5 g of amidinoacetic acid ethyl ester in ml of ethanol for 8 hours yields 2-amino-6-methyl-4-( l-naphthyl )-l ,4-dihydropyridine-3,5-dicarboxylic acid diethyl ester of melting point 174C (ethanol).

Yield: 62% of theory.

EXAMPLE 42 Upon heating a solution of 11.5 g of 2-cyanobenzylideneacetoacetic acid methyl ester and 7.2 g of amidinoacetic acid isopropyl ester in 100 ml of ethanol for 6 hours, 2-amino-6-methyl-4-(2-cyanophenyl)-l,4- dihydropyridine-3,S-dicarboxylic acid 3-isopropyl ester S-methyl ester of melting point 21 1C (ethanol) is obtained.

Yield: 72% of theory.

EXAMPLE 43 Upon boiling a solution of 11.5 g of 2-cyanobenzylideneacetoacetic acid methyl ester and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 8 hours, 2-amino-6-methyl-4-(2-cyanophenyl)-l,4- dihydropyridine-3,5-dicarboxylic acid 3-ethyl ester S-methyl ester of melting point 224C (ethanol) is obtained.

Yield: 66% of theory.

EXAMPLE 44 Upon boiling a solution of 14.8 g of Z-phenylbenzylideneacetoacetic acid ethyl ester and 6.5 g. of amidinoacetic acid ethyl ester in 100 ml of ethanol for 8 hours, 2-amino-6-methyl-4-(biphenyl-2-yl)-l,4-dihydropyridine-3,S-dicarboxylic acid ethyl ester of melting point 182C (ethanol) is obtained.

Yield: 41% of theory.

EXAMPLE 45 Upon heating a solution of 12.5 g of 3-nitrobenzylideneacetoacetic .acid methyl ester and 7.2 g of amidinoacetic acid npropyl ester in 100 m1 of ethanol for 6 hours, 2-amino-6-methyl-4-(3-nitrophenyl)-l,4- dihydropyridine-3,5 dicarboxylic acid 3-n-propyl ester 5-methyl ester of melting point C (ethanol) is obtained.

Yield: 69% of theory.

EXAMPLE 46 Upon heating a solution of 12.2 g of (2-thenylidene)- acetoacetic acid ethyl ester and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 4 hours, 2.- amino-6-methyl-4-(2-thenyl)-1,4-dihydropyridine-3 ,5- dicarboxylic acid diethyl ester of melting point C (ethanol) is obtained.

Yield: 73% of theory.

EXAMPLE 47 Upon heating a solution of 10.9 g of henzylideneacetoacetic acid dimethylamide and 5.0 g of amidinoacetamide in 100 ml of ethanol for 8 hours, 2-amino-6-methyl-4-phenyl-5-(N,N-dimethylaminocarbonyl )-1 ,4-dihydropyridine-3-carboxy1ic acid amide of meltingpoint 236C (ethanol) is obtained.

Yield: 50% of theory. i

EXAMPLE 4:;

Heating a solution of 10.9 g of benzylideneacetoacetic acid dimethylamide and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of methanol for 6 hours yields 2-amino-6-methyl-4-phenyll ,4-dihydropyridine-3 ,5- dicarboxylic acid 3-ethyl ester 5-(N,N-dimethylamide) of melting point 230C (alcohol).

Yield: 61% of theory.

EXAMPLE 49 Boiling a solution of 13.2 g of 2-nitrobenzylideneacetoacetic acid ethyl ester and 7.2 g of amidinoacetic acid isopropyl ester in 100 ml of ethanol for 6 hours yields 2-amino-6-methyl-4-(2-nitrophenyl)- 1,4-dihydropyridine-3,S-dicarboxylic acid 3-isopropyl ester 5-ethyl ester of melting point 139C (isopropanol).

Yield: 39% of theory.

EXAMPLE 50 Boiling a solution of 13.2 g of 2-nitrobenzylideneacetoacetic acid ethyl ester and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 6 hours yields 2-amino-6-methyl-4-(2-nitrophenyl)- 1,4-dihydropyridine-3,5-dicarboxylic acid diethyl ester of melting point 159C (ethanol).

Yield: 52% of theory.

EXAMPLE 51 Upon heating a solution of 12.5 g of 2-nitrobenzylideneacetoacetic acid methyl ester and 7.2 of amidinoacetic acid isopropyl ester in 100 ml of ethanol for 8 hours, 2-amino-6-methyl-4-(2-nitrophenyl)-1,4- dihydropyridine-3,S-dicarboxylic acid 3-isopropyl ester 5 -methyl ester of melting point 203C (isopropanol) is obtained.

Yield: 50% of theory.

EXAMPLE 52 Upon heating a solution of 12.2 g of 2-cyanobenzylideneacetoacetic acid ethyl ester and 7.2 g of amidinoacetic acid n-propyl ester in 100 ml of ethanol for 8 hours, 2-amino-6-methyl-4-(2-cyanophenyl)-l,4- dihydropyridine-3,S-dicarboxylic acid 3-n-propyl ester S-ethyl ester of melting point 182C (ethanol) is obtained.

Yield: 62% of theory.

EXAMPLE 53 Upon heating a solution of 13.9 g of 3-nitrobenzylideneacetoacetic acid isopropyl ester and 7.2 g of amidinoacetic acid n-propyl ester in 100 ml of ethanol for 6 hours, 2-amino-6-methyl-4-(3-nitrophenyl)-1,4- dihydropyridine-3,S-dicarboxylic acid 3-n-propyl ester 5-isopropyl ester of melting point 199C (isopropanol) is obtained.

Yield: 75% of theory.

EXAMPLE 54 Heating a solution of 6.5 g of 3-cyanobenzaldehyde, 5.6 g of cyclohexane-1,3-dione and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 6 hours yields 2-amino-4-( 3-cyanophenyl)-l ,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester of melting point 262C (ethanol/dimethylformamide).

Yield: 56% of theory.

EXAMPLE 55 Upon heating a solution of 9.3 g of 3-bromobenzaldehyde, 5.6 g of cyclohexane-1,3-dione and 6.5 g of amidinoacetic acid ethyl ester in ml of ethanol for 8 hours, 2-amino-4-(3-bromophenyl)-l,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester of melting point 255C (ethanol) is obtained.

Yield: 44% of theory.

EXAMPLE 56 Upon boiling a solution of 9.3 g of 2-bromobenzaldehyde, 5.6 g of cyclohexane-l,3-dione and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 6 hours, 2-amino-4-(2-bromophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester of melting point 245C (ethanol) is obtained.

Yield: 46% of theory.

EXAMPLE 57 Upon heating a solution of 8.9 g of 3-carbethoxybenzaldehyde, 5.6 g of cyclohexane-l,3-dione and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 4 hours, 2-amino-4-(3-carbethoxyphenyl)-l,4,5,6,7,8- hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester of melting point 234C (ethanol) is obtained.

Yield: 54% of theory.

EXAMPLE 58 Upon heating a solution of 7.4 g of 2-azidobenzaldehyde, 5.6 g of cyclohexane-l,3-dione and 6.5 g of amidinoacetic acid ethyl ester in 100 ml of ethanol for 4 hours, 2-amino-4-(2-azidophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester of melting point 209C (ethanol) is obtained.

Yield: 58% of theory.

What is claimed is:

l. A compound of the formula:

i 11 R a 2 3 R C CR wherein R is hydrogen; lower alkyl; lower alkenyl; lower alkynyl; phenyl unsubstituted or substituted by one to three members selected from the group consisting of 1 to 3, montertiary lower alkyl, tertiary lower alkyl, 1 to 3 lower alkoxy, 1 to 3 halogeno, l nitro, 1 cyano, 1 to 3 trifluoromethyl, l to 3 aziod, l to 3 carbo(lower alkoxy), 1 to 3 lower alkylsulfonyl, 1 to 3 lower alkylsulfinyl, 1 to 3 lower alkylthio and l to 3 phenyl moieties; or naphthyl;

R and R are linked together and are alkylene of 2 to 4 carbon atoms; and

R is lower alkyl, lower alkoxy, lower alkoxy(lower alkoxy), lower alkenyloxy, lower alkynyloxy, amino, lower alkylamino or di(lower alkyl)amino.

2. A compound according to claim 1 which has the formula:

wherein R is hydrogen; lower alkyl; lower alkenyl; lower alkynyl; phenyl unsubstituted or substituted by one to three members selected from the group consisting of l to 3 montertiary lower alkyl 1 tertiary lower alkyl, 1 to 3 lower alkoxy, l to 3 halogeno, l nitro, l cyano, l to 3 trifluoromethyl, l to 3 azido, l to 3 carbo(lower alkoxy), 1 to 3 lower alkylsulfonyl, l to 3 lower alkylsulfinyl, l to 3 lower alkylthio and l to 3 phenyl moieties; or naphthyl; and

R is lower alkyl, lower alkoxy, lower alkoxy(lower alkoxy), lower alkenyloxy, lower alkynyloxy, amino, lower alkylamino or di(lower alkyl)amino.

3. The compound according to claim 2 which is 2- amino-4-( 3-nitrophenyl)-l ,4,5 ,6,7,8-hexahydro-5- oxoquinoline-3-carboxylic acid ethyl ester.

4. The compound according to claim 2 which is 2- amino-4-(2-nitrophenyl)-1 ,4,5 ,6,7 ,8-hexahydro-5- oxoquinoline-3-carboxylic acid ethyl ester.

5. The compound according to claim 2 which is 2- amino-4-methyl-l ,4,5 ,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.

6. The compound according to claim 2 which is 2 amino-4-( 3-chlorophenyl)-l ,4,5 ,6,7,8-hexahydro-5- oxoquinoline-3-carboxylic acid ethyl ester.

7. The compound according to claim 2 which is 2- amino-4-(naphthl -yl )-l ,4,5 ,6,7,8-hexahydro-5- oxoquinolinel3-carboxylic acid ethyl ester.

8. The compound according to claim 2 which is 2- amino-4-( 2-cyanophenyl )-l ,4,5 ,6,7,8-hexahydro-5- oxoquinoline-3-carboxylic acid ethyl ester.

9. The compound according to claim 2 which is 2- amino-4-(2-trifluoromethyl-4-nitrophenyl)- 1,4,5 ,6,7,8-hexahydro-5 -oxoquinoline-3-carboxylic acid ethyl ester.

10. The compound according to claim 2 which is 2-amino-4 (2-nitr0-4,S-dimethoxyphenyl)-1,4,5,6,7,8- hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester.

11. The compound according to claim 2 which is 2-amino 4-( biphenyl-2-yl)-l ,4,5 ,6,7,8-hexahydro-5- oxoquinoline-3-carboxylic acid ethyl ester.

12. The compound according to claim 2 which is 2-amino-4-( 3-cyanophenyl )-l ,4,5 ,6,7,8-hexahydro-5- oxoquinoline-3-carboxylic acid ethyl ester.

13. The compound according to claim 2 which is 2-amino-4-( 3-bromophenyl)-l ,4,5 ,6,7,8-hexahydr-5- oxoquinoline-3-carb0xylic acid ethyl ester.

14. The compound according to claim 2 which is 2-amino-4-( 2-bromophenyl)-l ,4,5 ,6,7,8-hexahydro-- oxoquinoline-3-carboxylic acid ethyl ester.

15. The compound according to claim 2 which is 2-amino-4-( 3-carbethoxyphenyl )-1 ,4,5 ,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.

16. The compound according to claim 2 which is 2-amino-4-( 2-azidophenyl l ,4,5 ,6,7,8-hexahydro-5- oxoquinoline-3-carboxylic acid ethyl ester.

18 17. A process for the production of a compound of the formula:

' wherein R is hydrogen, lower alkyl; lower alkenyl; lower alkynyl; phenyl unsubstituted or substituted by one to three members selected from the group consisting of l to 3 montertiary lower alkyl 1 tertiary lower alkyl, 1 to 3 lower alkoxy, l to 3 halogeno, l nitro, l cyano, l to 3 trifluoromethyl, l to 3 azido, l to 3 carbo(lower alkoxy), l to 3 lower alkylsulfonyl, l to 3 lower alkylsulfinyl, l to 3 lower alkylthio and l to 3 phenyl moieties; or naphthyl and;

R is lower alkyl, lower alkoxy, lower alkoxy(lower alkoxy), lower alkenyloxy, lower alkynyloxy, amino, lower alkylamino or di(lower alkyl)amino;

which comprises the step of reacting an aldehyde of the formula RCl-lO, wherein R is as above defined, with a B-dicarbonyl compound of the formula R'COCH COR wherein R and R together are alkylene of 3 carbon atoms;

and with an amidine of the formula lH RC0CH CNH wherein R is as above defined: at a temperature of from 20 C to 250 C.

18. A process according to claim 17 wherein the reaction takes place in the presence of an inert, organic solvent.

19. A process according to claim 18 wherein the inert organic solvent is lower alkanol, an ether, glacial acetic acid, pyridine, dimethylformamide, dimethylsulphoxide or acetonitrile.

20. A process according to claim 18 wherein the reaction is conducted at the boiling point of the solvent.

21. A process according to claim 20 wherein the reactants are employed in substantially equimolar amounts.

22. A process according to claim 17 wherein R is lower alkyl or phenyl.

23. A process according to claim 17 wherein R is quinolyl, isoquinolyl, pyridyl, pyrimidyl, thenyl,

furyl and pyrryl, said heterocyclic ring being unsubstituted or substituted by one or two members selected from the group consisting of lower alkyl, lower alkoxy and halogeno.

24. A process according to claim 17 wherein R is lower alkyl, naphthyl, phenyl or phenyl substituted with from one to three substituents selected from the group as defined in claim 17.

25. A process according to claim 17 for the production of 2-amino-4-methyl-l,4,5,6,7,8-hexahydro-5- oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting acetaldehyde, cyclohexane-l ,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

26. A process according to claim 17 for the production of 2-amino-4-(3-chlorophenyl)-l,4,5,6,7,8-hexahydro-S -oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 3-chlorobenzaldehyde, cyclohexanel ,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

27. A process according to claim 17 for the production of 2-amino-4-( a-pyridyl)-l,4,5,6,7,8-hexahydro-- oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting pyridin-Z-aldehyde, cyclohexane-l ,3- dione and amidinoacetic acid ethyl ester and recovering the compound produced.

28. A process according to claim 17 for the production of 2-amino-4-(quinol-4-yl)-1,4,5,6,7,8-hexahydro- 5-oxoquinoline carboxylic acid 3-ethyl ester which comprises reacting quinolin-4-aldehyde, cyclohexane- 1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

29. A process according to claim 17 for the production of 2-amino-4-(4,-dimethoxypyrimid-S-yl)- 1 ,4,5 ,6,7 ,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 4,6-dimethoxy-pyrimidin-S-aldehyde, cyclohexane-l ,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

30. A process according to claim 17 for the production of 2-amino-4-( naphthl -yl)-l ,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting l-naphthaldehyde, cyclohexane- 1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

31. A process according to claim 17 for the production of 2-amino-4-(isoquinol-l-yl)-l,4,5,6,7,8-hexahydro-5 -oXoquinoline-3-carboxylic acid ethyl ester which comprises reacting isoquinolin l-aldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

32. A process according to claim 17 for the production of 2-amino-4-(6-methylpyrid-2-yl)-l,4,5,6,7,8- hexahydro-S-oxoquinoline-3carboxylic acid ethyl ester which comprises reacting 6-methylpyridin-2-aldehyde, cyclohexane-l,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

33. A process according to claim 17 for the production of 2-amino-4-(2-cyanophenyl)-l,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 2-cyanobenzaldehyde. cyclohexane-l ,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

34. A process according to claim 17 for the production of 2-amino-4-(Z-trifluoromethyl-4-nitrophenyl)- 1,4,5 ,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl :ester which comprises reacting 2-tri- 20 fluoromethyl-4-nitrobenzaldehyde, cyclohexane-l ,3- dione and amidinoacetic acid ethyl ester and recovering the compound produced.

35. A process according to claim 17 for the production of 2-amino-4-(2-nitro-4,5-dimethoxyphenyl)- l ,4,5 ,6,7 ,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 6-nitroveratraldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

36. A process according to claim 17 for the production of 2-amino-4-(biphenyl-2-yl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting biphenyI-Z-aldehyde, cyclohexane- 1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

37. A process according to claim 17 for the production of 2-amino-4-(3-cyanophenyl)-l,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 3-cyanobenzaldehyde, cyclohexane-l ,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

38. A process according to claim 17 for the production of 2-amino-4-(3-bromophenyl)-l,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 3-bromobenzaldehyde, cyclohexane-l ,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

39. A process according to claim 17 for the production of 2-amino-4-(2-bromophenyl)-l,4,5,6,7,8-hexahydro-S -oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 2-bromobenzaldehyde, cyclohexanell,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

40. A process according to claim 17 for the production of 2-amino-4-(3-carbethoxyphenyl)-l,4,5,6,7,8- hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 3-carbethoxybenzaldehyde, cyclohexane-l ,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

41. A process according to claim 17 for the production of 2-amino-4-(2-azidophenyl)-l,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 2-azidobenzaldehyde, cyclohexane- 1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

42. A process according to claim 17 for the production of 2-amino-4-(3-nitrophenyl)-l,4,5,6,7,8-hexahydro-S-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 3-nitrobenzaldehyde, cyclohexanel ,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.

43. A process according to claim 17 for the production of 2-amino-4-(2-nitrophenyl)-l,4,5,6,7,8-hexahydr0-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 2-nitrobenzaldehyde, cyclohexanel ,3-di0ne and amidinoacetic acid ethyl ester and recovering the compound. prpduaced; 

1. A COMPOUND OF THE FORMULA:
 2. A compound according to claim 1 which has the formula:
 3. The compound according to claim 2 which is 2-amino-4-(3-nitrophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 4. The compound according to claim 2 which is 2-amino-4-(2-nitrophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 5. The compound according to claim 2 which is 2-amino-4-methyl-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 6. The compound according to claim 2 which is 2-amino-4-(3-chlorophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 7. The compound according to claim 2 which is 2-amino-4-(naphth-1-yl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline13-carboxylic acid ethyl ester.
 8. The compound according to claim 2 which is 2-amino-4-(2-cyanophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 9. The compound according to claim 2 which is 2-amino-4-(2-trifluoromethyl-4-nitrophenyl)-1,4,5,6,7,8-hexahydro-5 -oxoquinoline-3-carboxylic acid ethyl ester.
 10. The compound according to claim 2 which is 2-amino-4-(2-nitro-4,5-dimethoxyphenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 11. The compound according to claim 2 which is 2-amino-4-(biphenyl-2-yl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 12. The compound according to claim 2 which is 2-amino-4-(3-cyanophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 13. The compound according to claim 2 which is 2-amino-4-(3-bromophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 14. The compound according to claim 2 which is 2-amino-4-(2-bromophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 15. The compound according to claim 2 which is 2-amino-4-(3-carbethoxyphenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3 -carboxylic acid ethyl ester.
 16. The compound according to claim 2 which is 2-amino-4-(2-azidophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester.
 17. A process for the production of a compound of the formula:
 18. A process according to claim 17 wherein the reaction takes place in the presence of an inert, organic solvent.
 19. A process according to claim 18 wherein the inert organic solvent is lower alkanol, an ether, glacial acetic acid, pyridine, dimethylformamide, dimethylsulphoxide or acetonitrile.
 20. A process according to claim 18 wherein the reaction is conducted at the boiling point of the solvent.
 21. A process according to claim 20 wherein the reactants are employed in substantially equimolar amounts.
 22. A process according to claim 17 wherein R is lower alkyl or phenyl.
 23. A process according to claim 17 wherein R is quinolyl, isoquinolyl, pyridyl, pyrimidyl, thenyl, furyl and pyrryl, said heterocyclic ring being unsubstituted or substituted by one or two members selected from the group consisting of lower alkyl, lower alkoxy and halogeno.
 24. A process according to claim 17 wherein R is lower alkyl, naphthyl, phenyl or phenyl substituted with from one to three substituents selected from the group as defined in claim
 17. 25. A process according to claim 17 for the production of 2-amino-4-methyl-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting acetaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 26. A process according to claim 17 for the production of 2-amino-4-(3-chlorophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 3-chlorobenzaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 27. A process according to claim 17 for the production of 2-amino-4-( Alpha -pyridyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting pyridin-2-aldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 28. A process according to claim 17 for the production of 2-amino-4-(quinol-4-yl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-carboxylic acid 3-ethyl ester which comprises reacting quinolin-4-aldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 29. A process according to claim 17 for the production of 2-amino-4-(4,6-dimethoxypyrimid-5-yl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 4,6-dimethoxy-pyrimidin-5-aldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 30. A process according to claim 17 for the production of 2-amino-4-(naphth-1-yl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 1-naphthaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 31. A process according to claim 17 for the production of 2-amino-4-(isoquinol-1-yl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting isoquinolin-1-aldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 32. A process according to claim 17 for the production of 2-amino-4-(6-methylpyrid-2-yl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3 -carboxylic acid ethyl ester which comprises reacting 6-methylpyridin-2-aldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 33. A process according to claim 17 for the production of 2-amino-4-(2-cyanophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 2-cyanobenzaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 34. A process according to claim 17 for the production of 2-amino-4-(2-trifluoromethyl-4-nitrophenyl)-1,4,5,6,7,8-hexahydro-5 -oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 2-trifluoromethyl-4-nitrobenzaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 35. A process according to claim 17 for the production of 2-amino-4-(2-nitro-4,5-dimethoxyphenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 6-nitroveratraldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 36. A process according to claim 17 for the production of 2-amino-4-(biphenyl-2-yl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting biphenyl-2-aldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 37. A process according to claim 17 for the production of 2-amino-4-(3-cyanophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 3-cyanobenzaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 38. A process according to claim 17 for the production of 2-amino-4-(3-bromophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 3-bromobenzaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 39. A process according to claim 17 for the production of 2-amino-4-(2-bromophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 2-bromobenzaldehyde, cyclohexane11,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 40. A process according to claim 17 for the production of 2-amino-4-(3-carbethoxyphenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3 -carboxylic acid ethyl ester which comprises reacting 3-carbethoxybenzaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 41. A process according to claim 17 for the production of 2-amino-4-(2-azidophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 2-azidobenzaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 42. A process according to claim 17 for the production of 2-amino-4-(3-nitrophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 3-nitrobenzaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced.
 43. A process according to claim 17 for the production of 2-amino-4-(2-nitrophenyl)-1,4,5,6,7,8-hexahydro-5-oxoquinoline-3-carboxylic acid ethyl ester which comprises reacting 2-nitrobenzaldehyde, cyclohexane-1,3-dione and amidinoacetic acid ethyl ester and recovering the compound produced. 